Impacted teeth refer to teeth that are stuck and cannot erupt into function. The most common impacted teeth are wisdom teeth. They are usually extracted once they start developing problems. Other teeth can also become impacted. The second most common impacted tooth is the maxillary cuspid (upper eyetooth). The cuspid tooth is a critical tooth in the dental arch and is responsible for holding and tearing food apart. It has one root, which is usually the longest root in the mouth.